I usually round out my Shadyside vintage shopping adventures with a trip to Hey Betty, after I leave Eons. It's a smaller store, but the selection is still very good. Last time we were here, my husband got a skinny tie and a trench coat for very reasonable prices. The costume jewelry cases in the center of the store are chock-full of sparkely goodness. There are even some random home decor items in the mix.
The owner (or at least who I perceive to be the owner, since he's the only one behind the counter when I shop here) is pleasant and will help you find your size if you ask. There are dressing rooms. All in all, a cute little vintage shop that is definitely worth visiting.